#include <stdio.h>
#include <string.h>
int string_to_int(const char *str);
int main(int argc, char *argv[]) {
  if (argc != 4) {
    printf("ERROR! ARGC NOT 4\n");
    return 0;
  }

  int a = string_to_int(argv[1]), b = string_to_int(argv[3]);
  switch (argv[2][0]) {
  case '+':
    printf("%d\n", a + b);
    break;
  case '-':
    printf("%d\n", a - b);
    break;
  case '*':
    printf("%lf\n", (double)a * b);
    break;
  case '/':
    printf("%lf\n", (double)a / b);
    break;
  default:
    printf("EROOR%c", argv[2][0]);
    break;
  }
}

int string_to_int(const char *str) {
  int ret = 0;
  for (int i = 0; i < strlen(str); i++) {
    ret = ret * 10 + (int)(str[i] - '0');
  }
  return ret;
}
